Waterslide amusement devices have been popular for decades. In the simplest waterslide, a rider climbs a stairwell located in a tower. The rider then enters an entrance of the waterslide and is propelled by gravity along the waterslide until splashing into a pool located at an end of the waterslide. Water flows down the waterslide along with the rider to decrease friction and enhance the entertainment value of the ride. Thus, a rider coasts along a slippery surface from a higher elevation to a lower elevation, either in a straight line path or on a path that includes curves. One variation of this approach has been to introduce undulations into the waterslide, so that the rider is propelled by gravity along a rollercoaster-like progression of downhill and uphill runs.
The “rider” can be an individual using the waterslide amusement device, for example in a sitting or prone position, or one or more persons using the waterslide amusement device on a mat, raft, tube or other conveyance device designed to slide on the waterslide surface.
Waterslide amusement devices that rely solely or primarily on gravity to propel the rider are expensive to manufacture and construct because they typically require the construction of a large, high tower, and an intricate elevated framework for supporting the waterslide high above the ground. One solution to this problem has been to provide a lift mechanism to raise a rider to a starting height, eliminating the need for the rider to climb stairs to ascend the tower. However, such lift mechanisms generally convey the rider at a constant speed, and add no excitement to the rider's experience. Some waterslide amusement devices include one or more variable speed conveyor belts interfaced with the slide for transporting the rider along uphill sections of the slide path (for example, as described in U.S. Pat. No. 7,371,183). The conveyor system may further include a control system having a sensor for sensing the speed of the rider. The control system can be adapted to control the speed of the variable speed conveyor belt based upon the sensed speed of the rider.
Another approach has been to propel the rider up an inclined waterslide surface or accelerate the rider along downhill and uphill segments of the slide using water jets, rather than have the rider propelled by gravity alone (for example, as described in U.S. Pat. No. 5,213,547). A series of water jets may be used to direct high-pressure water along the waterslide surface, and in the process propel the rider along the slide path. Although effective, this approach has certain limitations. If the force of the jets is too low then riders may only be conveyed a short distance along the slide path. If the jets are too powerful and the rider moving too slowly, then the rider may experience a jerky ride. Furthermore, if the force of the water jets propelling the rider is not adjusted then riders of different weights may be accelerated along the waterslide for different distances at different speeds and with different consequences for the rider's experience. Lighter riders may be propelled up a hill too far or too forcefully, at unsafe or undesirably high speeds. Heavier riders may move too slowly to provide sufficient excitement, or even too slowly to reach the crest of a hill. If the rider fails to reach the crest, the rider may slide backwards into the valley between uphill and downhill segments, creating a safety hazard, and requiring intervention to complete or terminate the ride.
Some waterslide amusement devices use rider speed traps, in which the speed of the rider is measured by timing the rider's travel along a slide path between two or more photocells. In some cases, the water volume and flow rate of the water jets are adjusted based on the measured speed of the rider. One problem with this method is that the operation of the photocells can be adversely affected by spray, and can be triggered by other extraneous motion in addition to the passage of the rider. False readings from the photocells can generate errors in the control system and can constitute a safety hazard. Also, measurement of rider speed at a particular location is not necessarily a reliable determinant of the force that will need to be applied to the rider in order for the rider to safely negotiate a downstream portion or feature of the slide path with an appropriate degree of excitement.
The present approach takes into account the inertia of the rider.